Fabrication of kaolin hollow fibre membranes for bacteria removal

Abstract

This study examines the influence of the particle size, extrusion rate and sintering temperature on the characteristics of kaolin hollow fibre membranes. In addition, the produced membranes were applied for bacteria removal from an aqueous suspension. The milling process reduced the size of kaolin particles from 8.7 to 5.1 μm and greatly enhanced the morphology and mechanical resistance of the produced membranes. The increase in the sintering temperature up to 1250°C caused crystallographic phase modifications in the crude kaolin, which were mainly assigned to transformations of quartz and kaolinite to mullite and cristobalite phases. The fibres sintered at 1250°C have bending strength of 145MPa, but this relatively high sintering temperature caused a substantial particle densification and drastic decrease of the membrane water permeability. The kaolin hollow fibre membranes enabled almost total removal of the Enterobacter bacteria from an aqueous suspension.

Keywords

• ceramic membrane
• kaolin
• asymmetric hollow fibre
• phase inversion
• bacteria removal